A large and varied market exists for current data on the size and characteristics of populations and households living in sub-county areas (zip codes circles, and market-driven polygons). Unfortunately, sub- county estimates from national demographic data vendors often differ dramatically from what is well-known locally. We improve upon vendor estimates by applying an innovative version of the "housing unit" approach in which we: use housing-based tax assessor data instead of electric utility counts or building permit data; add valuable predictive information on "house type" and "number of bedrooms" to the basic equation; geocode all housing units to precise lat/long co-ordinates so that baseline counts can be accurately aggregated to any user-defined geography whenever possible, baseline our estimates to 1990 Census data The resulting "estimates" database, computed for the six South Florida counties that make up our market, can be integrated with health client data to significantly improve and refine: denominators for populations at risk; sampling frames for surveys; inputs to model-based health research; identification/description of target populations. Similar applications exist in many other industries. Although we apply our methodology locally, it can easily be extended nationwide by other local-area practitioners. PROPOSED COMMERCIAL APPLICATIONS: This research initially results in a digitized. point-level population and household estimates database and an aggregated. census and postal geography-level database for six South Florida counties. We will aggressively market the data through local area contacts (Chambers of Commerce, Economic Development Agencies, etc.). We are also developing innovative mapping and tabular templates for standardized reports for price-sensitive clients. We expect the product market to closely mimic our current client database -- hospital districts and health care providers, municipalities, electric utilities, banks. real estate firms. local entrepreneurs (particularly start-ups), planning agencies, research firms, etc.